Serpentia, Custodia, Protego
by DrewbearSCP
Summary: Blaire Roth only wanted to learn more about the world of magic. But when she gets caught up in the schemes of older students Alto Clef, Everett Mann, and others, she learns more than she bargained for. SCP Foundation staff x Harry Potter
1. Cake and Feathers

"Happy Birthday!"

Blaire's father and younger brother pulled crackers with a loud pop as the newly 11-years-old girl blew out the candles on her cake. Her mother was recording everything on her phone as the flames sputtered and bent before finally going out, then joined in the applause.

"What did you wish for!" Blaire's younger brother Tom was always a bit demanding, but what did you expect from a 7 year old?

Their dad shushed Tom. "Now, now, telling your wish means it won't come true."

Truth be told, Blaire had wished that she could do magic, like the people in the bedtime stories her dad had told her when she was younger. The closest thing to magic that she could do was make sparks jump off her cat's fur when she was upset, and Tom could do that when he was 2 and throwing tantrums, so it wasn't like it was anything __special__ _._ Still, she could fantasize.

After everyone got a slice of cake (chocolate with strawberry icing!), Blaire unwrapped her presents. She'd be having a second, larger party with her school friends the following weekend, but this was just for the family, as per their tradition.

She opened Tom's present first, a drawing of her and Joseph, the family cat. It wasn't the world's best, but Tom had a knack and passion for art that made his works quite a bit ahead of his peers. Blaire thanked him with a smile and promised that she'd hang it on the cork-board in her room, which left him beaming in pride. The present from Mum and Dad was next: a new MP3 player! 64 gigs! She thanked them enthusiastically and barely restrained herself from running to the computer in the family room to load it up with her favorites. Dad waved her on with an indulgent smile (he'd always been a bit hopeless with computers) and Mum came over to help her get the player set up and working.

Blaire was deep in the middle of the hard choice between loading it up with One Direction, Adele, Bea Miller, or just loading it up with everything she had, when she half-heard a tapping at the window in the kitchen. She looked up in brief curiosity, only to see her Dad sliding open the window and… letting in an owl? It was the middle of the afternoon, what was an owl doing out? And why was her Dad letting it in?

Blaire dug out her phone to take pictures while asking her mother, "Mum, what's Dad doing with that owl?"

Her mother jerked her head up from the computer monitor and over towards the kitchen, then sighed as Dad lowered the owl to the kitchen table. "Christ. I'd hoped…" she said, quietly and absently.

She motioned Blaire up and over to the kitchen. "Come on, dear. It's time we had a family discussion."


	2. The First Day

"SLYTHERIN!"

Blaire pulled the ratty hat off her head to the applause of a quarter of the room. She smiled, weakly, as the nervous anticipation that had just filled her was exchanged for a nervous shyness. She stood and walked over to the long table draped in green and silver, and sat down at the first open spot at the end of the bench. The other first years who'd already seated themselves had the same slightly queasy look of relief and nervousness on their faces. As Roth looked down the table at the older students to see who she would be sharing a dorm with, she noted that many of them were alternating between speculative looks towards their new first years and speculative looks at the children still unassigned.

The rest of the Sorting passed in a blur. Two more students sat down at the table of her new House and she wondered what they were like. Victor something and Rebecca whosit. Eight students total. She hoped they got along.

Blaire's smile grew as her relief began to overpower her nervousness, and she had a wide grin across her face as the Headmistress finished giving her speech. She didn't know of any reason yet that she'd have to go onto a blocked-off corridor and naming something the Forbidden Forest seemed fairly self-explanatory. But she supposed that someone might be stupid.

When the food appeared in front of her on the table, Blaire startled a little. She'd been expecting servants to bring out the dishes, like the waiters at the fancy restaurant her parents had taken her to for her uncle's wedding. The food all looked so good, too! There was _so much_ that happened by magic here. She was excited, but didn't know how she'd ever get used to it all.

The boy who'd sat next to her, Victor, nudged her with his elbow as he reached for a plate of potatoes. Through a mouthful of food, he half-mumbled at her, "Eat up! The shepherd's pie is brilliant!"

Blaire nodded at him thankfully, a slight smile on her face, and reached for an unfamiliar dish of something blue and wobbly. If it was magic food, it ought to be good no matter what!

* * *

Everett Mann kept an eye on the new Slytherins as he filled his plate. He recognized the last names of most of them, but he'd never heard of two of them. He'd have to find out more about those two, Redd and Roth. You never knew when someone might have family connections that could be of use to you.

The boy across from him kicked him under the table. Mann looked up into the eyes of his year-mate, Alto, and raised his eyebrow questioningly.

"Lay off the eyes, Mann. Let the firsties get through their first meal before you start scaring them. You can start sizing them up for 'experiments' after we get back to the common room."

Alto waggled his eyebrows at Mann when he said "experiments" and snorted in amusement at the unamused look on his friend's face. Mann nodded and speared some sausages to transfer to his plate, then began cutting them into neat, even discs. He sunk into a mild reverie as he ate and contemplated which potions he might try on the firsties before they learned to not trust anything he gave them to eat or drink.

* * *

Alto slipped ahead of the rest of the Slytherins as they all headed back to their dorms. Personally, he found the cool and green-tinged atmosphere of the common room to be somewhat aloof, more so than he cared for, but it did to keep a presence. To watch how the others interacted with each other, if nothing else. Besides, it was almost his duty to stake claim on the best seat before any other third year got to it.

He made it to the hidden entrance ahead of everyone but one of the seventh-year prefects, Callista Arctos. She wasn't so bad, for an upperclassman. Alto felt that she was too wrapped up in the story she was telling herself, though, that she had to be The Good Slytherin, so as to prove to her family that she wouldn't turn to the Dark Side. He paused and looked at her inquisitively.

She nodded at him coolly and told him, "The password this week is 'parity." As the wall shuffled open behind her, Alto grinned back and thanked her as he entered.

A smattering of older Slytherins were already gathered in small groups in the common room, but it looked like Alto had been speedy enough to grab a high-backed chair near to, but not _too_ near to, the large fireplace. The internal Slytherin hierarchy wouldn't let him comfortably claim a better location until he was older or better positioned socially. But it didn't unduly cause him concern. So long as he had a clear line of sight around the room, he was satisfied.

He settled into the chair just in time for the contingent of firsties escorted by fifth- and sixth-year prefects to arrive. They looked nervous, which was to be expected, and there was one on the end who looked decidedly green. __Very__ green, in fact. It looked like his skin was actually changing complexion and… yes, his hair had a slight silver sheen to it now as well.

 _A Metamorphmagus. Interesting. Best keep an eye on him. Too easy for someone like that to think of themselves as a Hero and get hurt. Especially if he thinks he has to Uphold Slytherin Honor or something._

Once the firsties were all herded into the center of the room, where everyone could get a good look at them, Callista came down the hallway to the rest of the school and looked them over imperiously, arms crossed.

"Welcome to Slytherin House. You've been sorted into the best of the Houses, and will be expected to represent that.

"We're the best because we _have_ to be the best. If you didn't notice during the Sorting, allow me to inform you that the other Houses generally don't like us. Expect indifference at best, and open hatred at worst. You might think that I'm being cruel to tell you this before you've even seen your dorms, but it would be crueler to let you discover it on your own.

"Because of this, there is one rule that you will be expected to follow at all times: Present a unified front in public. You can dislike or fight or prank other members of the House as much as you can get away with, __so long as no other House knows__ _._ As far as the other Houses know, we're all lovey-dovey and to mess with __any__ of us is to mess with __all__ of us. Remember that."

As Callista continued on with the rest of her introduction speech, Alto noted tiny details in the body language of the eight firsties, mentally ranking them on a scale of "unnamed background character" to "main protagonist". There were really only three that he thought he'd need to keep tabs on: the Metamorphmagus, that brown-haired girl with the serious face, and his cousin Victor Sharpe. The family would be disappointed if he let Cousin Victor come to any permanent harm, after all.

* * *

Blaire lay in her bed, the nervousness and excitement of the day keeping her awake. It had been such a busy day, capped by a rather brusque welcome to Slytherin House. She absently stroked her cat, Joseph, as she thought about it. Her father had told her that he'd be happy for her no matter what House she ended up in, but so many kids on the train had been scared of being sorted into Slytherin. And what that prefect had said to them hadn't helped set her mind at ease at all.

But she would muddle through. Dad had been in Hufflepuff and had instilled in her an ethic of perseverance. And Mum would be so disappointed if she didn't do her best. Blaire didn't know if the cell phone her mother had given her before leaving would get coverage out here, but she would try to send them a text in the morning. If that didn't work, Dad had said something about owls. She would ask one of the older students if it came to that. But even if she didn't get signal, she was going to take a lot of pictures and video with her phone so she could show them to Mum and Dad and Tom when she went home at Christmas.

Despite her belief that she wouldn't __ever__ fall asleep from all the excitement, Blaire eventually drifted off to sleep. Joseph took the opportunity to wriggle free from her lazy arm and poked his nose through the heavy curtains around the bed. A trio of lit globes hung from the ceiling, shedding a dim silver light over the room, more than enough for the tabby cat to see clearly.

He didn't particularly like this place so far; it smelled damp and there were far too many new, strange people and animals all around. Nevertheless, it was his duty to explore every nook and cranny, if for no other reason than to find the best place to express his displeasure with being uprooted from his nice warm home. He slipped through the curtains of Blaire's bed and took a preliminary tour of the octagonal room. Plenty of places for him to jump onto and perch, but a disappointingly small number of things to knock over.

After spending a good half hour carefully inspecting the room, Joseph started to try to find a way out of the room. He'd always had free run of the house and refused to accept that that would change in this new place. The door wasn't cracked open like all doors should be, though, and he was preparing to break out Yowl #3 ("Let Me In/Out!") when a midnight-black cat popped her head __through__ the bottom of the door. He startled back, back arching and fur puffing while he hissed a warning at her. She spared him a single disinterested glance, sneezed at him, then came all the way through. While Joseph kept a wary eye on her, she made a quick pad around the room, sniffing at each of the canopied beds, before coming back over to the door.

Joseph raised a paw to smack at her, but the other cat's head whipped around and stared straight at him, a hard, defiant look in her eyes. Joseph wavered, then pulled his paw to his mouth to lick it, acting as if cleaning himself is what he'd meant to do the entire time. The other cat sniffed in disdain and walked back through the same section of door, leaving Joseph behind. Joseph sniffed at the section of door the other cat had walked through, then tentatively headbutted it. Solid.

Thoroughly discomfited at this point, Joseph paced around the room again, trying to decide where, exactly, he would crap so as to make his displeasure clear.


End file.
